Counting method

ABSTRACT

A counting method comprising the steps of weighing a number of articles dividedly by n weighing machines, dividing the weights measured by the weighing machines by the unit weight of the articles to find the respective numbers of articles in the weighing machines, calculating combinations of these numbers to find the combination numbers associated with the respective combinations, finding a particular combination whose combination number is equal or closest to a set number, and discharging the groups of articles corresonding to the particular combination from the corresponding weighing machines, while calculating a new unit weight from a weight or weights measured by one or a plurality of the weighing machines and from the number or numbers of articles in this one or plurality of the weighing machines, such new unit weight being used for the next calculation of numbers.

The present invention relates to a method of counting articles withincreased accuracy in combinatorial counting of articles which havevariations in the weight of a single article (hereinafter referred to asunit weight), such as packaged cups of bolts, nuts, and milk.

In the case of combinatorial counting which comprises the steps ofweighing groups of articles respectively by a plurality of weighingmachines, converting the weight measured by each weighing machine intothe number of articles in each group, and performing combinatorialcalculations of the individual weights to obtain a predetermined numberof articles, said conversion of weights into numbers is performed bydividing each measured weight by the unit weight, or the weight of asingle article. However, if there is an error in the unit weight, thisresults in an error in the number of articles calculated for eachweighing machine and hence an error in the combination number obtainedby performing combinatorial calculations, thus making accurate countingimpossible. Further, the greater the number of articles weighed by asingle weighing machine, the greater the error in the calculated number.Therefore, in order to calculate the number of articles accurately, itis necessary to find the unit weight accurately. However, since articlesvary in the unit weight, as described above, it would be nonsense toweigh a single article accurately for the purpose of finding the unitweight. Thus, it would be better to find the unit weight by weighing anumber of articles and dividing their weight by the number of articles;the greater the number of articles to be weighed, the more accuratelycan the unit weight be ontained. Therefore, it is preferable that thevalue for the unit weight of articles which is determined by suitablemeans at the start of weighing operation be replaced by a new valueobtained by calculation in each weighing operation. In order to find theunit weight more accurately, there is a method of renewing the unitweight for each weighing operation, which comprises the steps ofinitially charging each weighing machine with a lesser number ofarticles and gradually increasing the number of articles to be chargedinto each weighing machine in successive weighing operations until itcorresponds to the number of articles to be obtained. Further, wherecombinatorial counting is repeated, there are cases where the unitweight of articles gradually decreases (or increases) as a whole withthe lapse of time. This occurs, e.g., when milk is charged into cups,because the viscosity of milk varies with ambient temperature. In thiscase also, it is necessary to calculate the unit weight of articles forrenewal in each weighing operation.

Accordingly, it is an object of the present invention to provide moreaccurate combinatorial counting by calculating the unit weight from theweight or weights of articles weighed by a single or a plurality ofweighing machines in each combinatorial operation, to renew the valuefor the unit weight so as to obtain a more accurate value for the unitweight.

According to the invention, since the unit weight for calculating thenumber of articles from their weight can be obtained from the weight ofa number of articles which is actually calculated, the counting accuracycan be increased. According to the invention, even if the unit weight ofarticles gradually varies during counting, such variations can beautomatically accommodated by renewing the unit weight of articles ineach counting operation, so that very accurate counting can be effected.Further, according to the invention, since the unit weight isautomatically renewed by weighed articles themselves throughcombinatorial weighing, the initial setting of unit weight can be veryaccurately effected, even in the case of weighing a large number ofarticles, by initially weighing a relatively small number of articlesand then gradually increasing the number of articles to be weighed.

A combinatorial counting method has heretofore been known, comprisingthe steps of charging a plurality of weighing machines each with anumber of articles with suitable variations, dividing the weight valueof articles obtained by each weighing machine by the unit weight ofarticles to find the number of articles, calculating combinations of theweights to find a particular combination which is equal or closest to aset number, and discharging the articles from the weighing machinescorresponding to said particular combination. Thus, in this countingmethod, if the unit weight of articles for finding the number ofarticles from the weighed value of the articles is fixed at theinitially set value, there is a possibility that the error in this setunit weight increases with respect to the unit weight of the articleswhich are to be actually weighed. This is because the value used forinitially setting the unit weight of articles is either a value obtainedby weighing usually a single or several articles by a separate weighingmachine or a value which is preset as the standard weight of sucharticle. Since the unit weight of articles will differ from article toarticle or vary with such factors as the conditions of the machine usedfor producing such articles and the quality of the material of thearticles, even if efforts are being made to keep the unit weight ofarticles at a fixed value, the unit weight will vary with the lapse oftime. Therefore, it is more preferable that the unit weight used in saidcombinatorial counting be obtained from the weighed value of a number ofarticles being actually weighed, by dividing said value by the number ofarticles.

With the above in mind, the present invention provides improvements.More particularly, the invention consists in weighing a large number ofarticles by n weighing machines, dividing the weight measured by eachweighing machine by the unit weight to find the number of articlescontained in each weighing machine, calculating combinations of theindividual numbers to find a particular combination which is equal orclosest to a set weight, while calculating a new unit weight from theweight or weights measured by one or a plurality of said weighingmachines and from the number or numbers of articles contained in saidweighing machine or machines, and using this new unit weight for thenext calculation of numbers.

The invention has many embodiments as to the method of finding a newunit weight after combinatorial counting. These embodiments will besuitably selectively used singly or in combinations, depending upon thekind of articles to be counted or upon the purpose of counting.

Thus, in a counting method comprising the steps of dividing the weighedvalues of articles obtained by a plurality of weighing machines by theunit weight to find the numbers, and calculating combinations of thesenumbers to find a particular combination equal or closest to a setnumber, the invention consists in dividing the weighed value of theactually weighed articles by the number of said articles to find theunit weight, the latter being then used as a new unit weight for thenext combinatorial counting, so that combinatorial counting can beperformed with very high accuracy. Further, even if the average unitweight of articles gradually varies during repeated combinatorialcounting, this is automatically compensated to allow combinatorialcounting to be effected with the proper unit weight at all times.

These and other objects and features of the invention will become moreapparent from the following description given with reference to theaccompanying drawings, in which:

FIG. 1 is a block diagram showing an example of the arrangement of thepresent invention;

FIGS. 2 through 4 are flowcharts showing different examples of theprocessing procedure in the example of the arrangement in FIG. 1; and

FIG. 5 is a block diagram of another embodiment of the invention.

In FIG. 1 showing a combinatorial counting apparatus according to thepresent invention using a microcomputer, 1₁ . . . 1_(n) denote nweighing machines for weighing articles, and 2 denote a multiplexer forsuccessively transferring analog weight voltages produced by theweighing machines 1₁ . . . 1_(n) in response to selection signals to belater described, said multiplexer being composed, e.g., of analogswitches. The numeral 3 denotes an A/D converter for converting analogweight voltages from the multiplexer 2 into digital weight signals; 4denotes an arithmetic control section composed of a microcomputer or thelike; 5 denotes a unit weight setting section for setting the unitweight of articles; 6 denotes a number setting section for setting thenumber of articles to be counted; 7 denotes a weight setting section forsetting the total weight of that number of articles which has been setby the number setting section 6; 8 denotes an upper weight limit settingsection for setting the upper limit weight for the total weight of a setnumber of articles; and 9 denotes a lower weight limit setting sectionfor setting the lower weight limit. FIG. 2 is a flowchart showing anexample of the operation of the arithmetic control section 4, which willnow be described.

The n weighing machines 1₁ . . . 1_(n) have been charged each with adivision of a number of articles. When a start signal a from a packagingmachine (not shown) for packaging counted articles is transferred to thearithmetic control section 4, the latter transfers a selection signal bto the multiplexer 2. In response to the selection signal, themultiplexer 2 transfers the analog weight voltages, which have beentransferred thereto from the weighing machine 1₁ . . . 1_(n),successively to the A/D converter 3, and the A/D converted weights arestored in the arithmetic control section 4. The arithmetic controlsection 4 divides each weight stored therein by the unit weight set bythe unit weight setting section 5 and rounds the quotient to the nearestinteger, thus converting the weights of the articles in the weighingmachines 1₁ . . . 1_(n) into the respective numbers of articles thereinand storing said numbers. The arithmetic control section 4 adds thestored numbers of articles in the weighing machines 1₁ . . . 1_(n) inaccordance with all of the combination codes indicating the combinationsof the weighing machines to calculate combination numbers for thecombination codes, stores these combination numbers and combinationcodes in pairs, and compares the set number set by the number settingsection 6 with all of the stored combination numbers to search for acombination code which agrees in number, and stores it. However, ifthere is no combination which agrees in number, it judges that countingis impossible, and turns on a warning lamp, for example, moving to asuitable error processing treatment. Further, the arithmetic controlsection 4 adds the weights of the articles in the weighing machines 1₁ .. . 1_(n) in accordance with the combination numbers which are equal tothe set number of calculate the combination weights and searches for acombination of weights, among these combination weights, which is equalor closest to the set weight set by the weight setting section 7 andstores such combination weight and combination code as a pair. Itcompares this stored combination weight with the upper weight limit setby the upper weight limit setting section 8 and the lower weight limitset by the lower weight limit setting section 9, and if this combinationweight is not between the upper and lower weight limits, it judges thatcounting is impossible, and turns on a warning lamp, for example, movingto a suitable error processing treatment. If said combination weightlies between the upper and lower weight limits, the arithmetic controlsection 4 transfers discharge signals in accordance with the combinationcode associated with said combination weight. The articles in theweighing machines corresponding to the discharge signals are discharged,so that articles whose number is equal to the set number are fed to thepackaging machine. At this time, the arithmetic control section 4calculates a new unit weight from the weight or weights of the articlesin a desired one or more of the weighing machines and the number ornumbers of articles therein and stores said new unit weight. The newunit weight is used when the numbers of articles are calculated from theweights of the articles in the weighing machines 1₁ . . . 1_(n) in thenext counting. In addition, there are various methods of finding thisnew unit weight, which will be later described in block.

Thereafter, the next counting operation will be performed in the samemanner as described above.

First, the weighing machines from which articles have been dischargedare fed with fresh articles and when a start signal a is transferred tothe arithmetic control section 4, the weights of articles in theweighing machines 1₁ . . . 1_(n) are stored in the same manner as in thepreceding case. These weights are divided by the new unit weight whichwas calculated in the preceding counting and stored, the quotients beingrounded to the nearest integers, whereby the weights of the articles inthe weighing machines 1₁ . . . 1_(n) are converted to the numbers ofarticles. As in the preceding case, a combination whose combinationnumber is equal to the set number and whose combination weight liesbetween the upper and lower weight limits and equal or closest to theset weight is searched for. If a combination which satisfies theseconditions is obtained, discharge signals are transferred from thearithmetic control section in accordance with this combination. In thiscase also, this combination weight which has been discharged is dividedby the set weight to calculate a new unit weight, which is stored inplace of the new unit weight which was calculated and stored in thepreceding counting operation and is used for the next countingoperation. Thereafter, the same procedure is followed and the unitweight is renewed for each counting operation.

As described above, the invention consists in calculating the number ofarticles in each weighing machine by a preset unit weight for the firstcombinatorial counting, and calculating and storing a new unit weightfor the next combinatorial counting, so that in and after the secondcombinatorial counting, the number of articles in each weighing machineis calculated by the new unit weight calculated and stored during thepreceding counting and the new unit weight is renewed for the nextcounting.

Some concrete methods of finding new unit weights in the abovearrangement will now be described.

A first method of finding new unit weights is characterized in that whendischarged signals are transferred from the arithmetic control section 4after combinatorial calculations in accordance with the result of saidcombinatorial calculations, the arithmethic control section 4 calculatesa new unit weight by dividing the weight of the discharged articles,i.e., the combination weight which is equal or closest to the setweight, by the number of discharged articles, i.e., the set number, saidnew unit weight being stored in the arithmethic control section 4 foruse in the next combinatorial calculation.

A second method of finding new unit weights is characterized in that thecombination weights in those combinations whose combination numbers areequal to the set number are rearranged in decreasing or increasingorder, and one combination weight which is at the middle of the series(i.e., median) is divided by that combination number to find a new unitweight.

The usefulness of this second method will now be described. In the casewhere the first method is used, if, for example, there are 5combinations whose combination numbers are equal to the set number andwhose combination weights are 199 g, 200 g, 196 g, 197 g, and 194 g, andthe set number is 200 g, then the combination whose combination weightis 200 g will be discharged and a new unit weight will be calculated bydividing this combination weight 200 g by the combination number.However, where combination weights are distributed more predominantly inthe smaller-value region (or larger-value region) with respect to theset weight, as in this case, a new unit weight can be found moreaccurately by dividing the combination weight which lies in the middleof the combination weight series (median) (in the above example, 197 g)by the combination number than by dividing the combination weight whichis equal or closest to the set weight by the combination number.

In the first and second methods, a new unit weight is calculated fromthe combination weight in one combination and the combination number inthat combination. However, it is possible to calculate a new unit weightfrom the combination weights in a plurality of combinations and thecombination numbers in those combinations and to store said new unitweight. This will now be described as third through sixth methods.

The third method of finding new unit weights comprises the steps ofdividing the combination weights in all or any of those combinationswhose combination numbers are equal to the set number respectively bysaid combination number to find unit weights, calculating the average ofthese unit weights, and storing said average as a new unit weight.

The usefulness of this third method will now be described. Where aplurality of combinations whose combination numbers are equal to the setnumber are obtained, a combination whose total weight is closest to theset total weight to be discharged is selected from the combinations andthe articles are discharged from the corresponding weighing machines. Inthis case, if a new unit weight is obtained by dividing the total weightof the discharged combination by the set number, errors will becomegreater when the unit weight is varying. That is, where the unit weightis varying, the total weight in each combination is also varying in thesame direction as the unit weight as a whole. In this case, it is betterto adopt a way of finding new unit weights which reflects the value ofthe varying total weight. Therefore, although what is discharged is thecombination closest to the set total weight, a new unit weight is foundby calculating a unit weight for each of the combinations which areequal to the set number and calculating the average of these unitweights, the new unit weight thus found being close to the average ofthe actual unit weights, which minimizes the probability of errors inindividual calculations.

The fourth method of finding new unit weights will be described. First,the upper and lower limits of the number of articles are provided. Ofthe calculated and stored combinations and their combination numbers,all or any of those combinations which are equal to the set number arestored, while those combinations whose combination numbers lie betweenthe upper and lower number limits are searched for and all or any ofthem are stored. The combination weights in these combinations which arestored under the condition of equality or lying between the upper andlower limits are calculated and stored, and the stored combinationweights are divided respectively by their combination numbers to provideunit weights, and the average of these unit weights is calculated toprovide a new unit weight.

The fifth method of finding new unit weights comprises the steps ofcalculating combinations, storing all said combinations and combinationweights, dividing all the stored combination weights respectively bytheir combination numbers to provide unit weights, and calculating theaverage of these unit weights to provide a new unit weight.

The sixth method of finding new unit weights comprises the steps ofcalculating the sum of individual combination weights, e.g., thecombination weights of all or any of those combinations whosecombination numbers lie between the upper and lower number limits toprovide the total weight, adding up their combination numbers to providethe total number, dividing said calculated total weight by the totalnumber to provide a unit weight, and using said unit weight as a newunit weight.

While the first through sixth methods are based on combination weights,it is also possible to calculate new unit weights with the weight of thearticles in each weighing machine taken into account. This will now bedescribed as the seventh through tenth methods.

The seventh method of finding new unit weights comprises the step ofdividing the weight of articles measured by a particular one of theweighing machines taking part in combinatorial counting operation by thenumber of the articles in said particular weighing machine, thusproviding a new unit weight. This calculated new unit weight is used inthe next combinatorial counting to calculate the number of articles fromthe weight of articles received in each weighing machine.

The eighth method of finding new unit weights is characterized in thatin the seventh method, the one weighing machine used for finding a newunit weight is changed with one selected from the other weighingmachines taking part in combinatorial counting in a predetermined orderfor each counting operation.

The usefulness of the eighth method is the removal of the disadvantageof fixing one weighing machine used for finding new unit weights. Moreparticularly, with said one weighing machine fixed, if the articles inthis particular weighing machine are not discharged in a series ofoperations, this means that the new unit weight is not renewed, failingto represent the unit weight of the present articles.

The nineth method of finding new unit weights comprises the steps ofdividing the weights of articles in all or any of the n weighingmachines respectively by the numbers of these articles to find unitweights, calculating the average of these unit weights, and storing saidaverage as a new unit weight.

The tenth method of finding new unit weights comprises the steps ofcalculating the total weight by adding up the weights of articles in allor any of the n weighing machines, calculating the total numbers byadding up the numbers of articles in these weighing machines, anddividing the calculated total weight by the calculated total number toprovide a new unit weight.

The eleventh method of finding new unit weights will now be described.

The first through tenth methods of finding new unit weights describedabove comprise the steps of converting weights found by the weighingmachines into numbers, calculating combinations of these numbers,discharging the articles from the weighing machines corresponding to aparticular combination which satisfies the conditions, recalculating aunit weight, storing the latter for use as a unit weight for the nextcombinatorial counting operation. Upon careful examination of the same,it is seen that all of the weights found by the weighing machines arenewly stored and divided by the newly stored unit weight to findrespective numbers. However, the discharge of articles on the basis ofthe result of the preceding calculation is not from all of the weighingmachines. That is, there are weighing machines in which articles fromthe preceding combinatorial counting remain without being discharged.However, the next calculation is performed by using the newly storedunit weight for conversion of weights measured by the weighing machinesinto numbers. As a result, there are weight values not divided by properunit weight, forming a major cause of errors in calculating the numberof articles. To elimnate this drawback, the conversion into numbers bythe use of a newly stored unit weight in the next calculation should belimited to those weighing machines which were emptied last time andnewly filled with articles. That is, the eleventh method of finding newunit weights is characterized in that for the weighing machines whichdid not discharge last time, calculation for conversion by the use ofthe new unit weight is not performed and instead the numbers into whichweights were converted last time are stored and used as such forcalculation of combinations. If calculation of combinations is performedby the use of the stored numbers, for those weighing machines which havenot discharged, until they discharge, the probability that numbers aremistaken because of the factors described above can be minimized. Inaddition, the eleventh method of finding new unit weights is performedtogether with any of the first through tenth methods.

Operation in which the eleventh method of finding new unit weights isperformed in the arrangement shown in FIG. 1 will now be described withreference to the flowchart of FIG. 3. The difference of the flowchart ofFIG. 3 from that of FIG. 2 is in the region extending from the start ofcalculation of combinations to the point where the arithmetic controlsection 4 stores those combinations which agree with the set number.This different operation alone will be described. When a start signal ais transferred to the arithmetic control section 4 from a packagingmachine (not shown), the arithmetic control section 4 outputs aselection signal b to the multiplexer 2. In accordance with theselection signal b, the multiplexer 2 picks up only those of theweighing machines 1₁ . . . 1_(n) which discharged last time andsuccessively transfers analog weight voltages to the A/D converter, theA/D converted weights being stored in the arithmetic control section 4.The arithmetic control section 4 divides the stored weights by the unitweight set by the weight setting section 5, rounds the quotients to thenearest integers, and converts the weights of the articles in theweighing machines 1₁ . . . 1_(n) which discharged last time. Inaccordance with all of the combination codes, the arithmetic controlsection 4 calculates combination numbers by performing predeterminedaddition from the numbers already stored for the weighing machines 1₁ .. . 1_(n) which discharged last time and the numbers which wereconverted and stored in the last calculation for the weighing machineswhich did not discharge last time, and stores these combination numbersand combination codes in pairs. The operation which follows is exactlythe same as that described with reference to FIG. 2.

The twelfth method of finding new unit weights will now be described.

The first through eleventh methods of finding new unit weights employthe way of storing a unit weight anew for each combinatorial countingoperation. However, it does not necessarily follows that the unit weightis substantially equal for each combinatorial counting operation or isincreasing or decreasing in the same direction. For example, if the unitweight repeats increase and decrease for each combinatorial countingoperation, it follows that with respect to the unit weight stored anewin a state where it changed in the increasing direction (decreasingdirection) in the last combinatorial counting operation, the unit weightof articles which take part in combinatorial counting operation thistime is changing in the decreasing direction (increasing direction),i.e., in the opposite direction. In this case, the result is that theunit weight is stored anew in the direction which lowers the accuracy ofconversion into numbers. To solve this problem, according to the twelfthmethod of finding new unit weights, renewal storage of unit weight isnot effected each time and instead unit weights obtained in n successivecombinatorial counting operations are stored and after the nth time, theaverage of these n unit weights will be stored for use as a new unitweight for the following n successive combinatorial counting operations.If renewal storage of unit weight is effected every nth time in thismanner, the probability of number conversion can be increased.

In addition, the twelfth method of finding new unit weights will be usedwith any of the first through eleventh methods used in the arrangementshown in FIG. 1 or will be used with any combination of these methods.

Operation in which the twelfth method of finding new unit weights isperformed in the arrangement shown in FIG. 1 will now be described withreference to the flowchart of FIG. 4. The difference of the flowchart ofFIG. 4 from that of FIG. 2 is in the region extending from the pointwhere the arithmetic control section 4 transfers discharge signals toweighing machines to the point where it waits for a start signal a fromthe packaging machine. This different operation alone will be described.When the arithmetic control section 4 outputs a discharge signal, thesame number of articles as the set number are discharged from theweighing machines corresponding to the discharge signals. At this time,the arithmetic control section 4 calculates a unit weight (A) bydividing the combination weight, which is equal or closest to the weightof the discharged articles, i.e., the set weight, by the number ofdischarged articles, i.e., the set number, stores said unit weight (A),and judges whether or not the number of times of calculation of suchunit weight (A) reaches the preset number n. If it does not reach thenumber n, the arithmetic control section waits for a start signal a fromthe packaging machine, performing the next combinatorial operation inthe same procedure as described with reference to the flowchart of FIG.2. If the number of times of calculation of unit weight (A) reaches thenumber n, the arithmetic control section adds up the n unit weights (A),which have been stored, and divides the sum by n, to find the averageunit weight, which is then used as a new unit weight for the followingnumber conversion. Thus, a new unit weight is calculated every nth time,and the same procedure is repeated.

While the arrangement shown in FIG. 1 is an example in which all of thedata to be processed are once converted into digital values, which arethen processed by arithmetic operations, it goes without saying that thepresent invention is also applicable to an arrangement for processinganalog values by arithmetic operations.

FIG. 5 shows a system in which analog weight voltages from n weighingmachines 11₁ . . . 11_(n) are transferred to an arithmetic controlsection 14 through a storage section which stores analog weightvoltages. The numeral 15 denotes a unit weight setting section forsetting the unit weight of articles by analog voltage; 16 denotes anumber setting section for setting by analog voltage the number ofarticles to be discharged; 17 denotes a weight setting section forsetting by analog voltage the total weight of that number of articleswhich is set by the number setting section 16; 18 denotes an upperweight limit setting section for setting by analog voltage the upperlimit of the total weight of a set number of articles; and 19 denotes alower weight limit setting section for setting by analog voltage thelower limit of the total weight of a set number of articles. When astart signal from a packaging machine (not shown) adapted to packagecounted articles is transferred to the arithmetic control section 14,combinatorial counting operation is performed in the same manner asdescribed with reference to the arrangement of FIG. 1, and a new unitweight is calculated by any of the first through twelfth methods offinding new unit weights or by any combination thereof.

In addition, in the present invention described above, a combinationwhose combination number is equal to the set number is found; however, acombination which is closest to the set number may be found. In thiscase, however, since the combination which is closest to the set numberis not always equal to the set number, a new unit weight will becalculated by dividing the combination weight by said closest number.

Further, of the combinations whose combination numbers are equal orclosest to the set number, any one combination without regard to thecombination weight, e.g., a combination initially found to be equal tothe set weight may be used to discharge articles. In this case,therefore, said upper and lower weight limit setting sections and weightsetting section are not needed.

Further, in the present invention described above, during combinatorialoperation, only that one of the combinations calculated previously whosecombination number is equal or closest to the set number is stored, andupon completion of all combinatorial operations, a combination whosecombination number is equal or closest to the set number in allcombinations may be found.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsthereof except as defined in the appended claims.

What is claimed is:
 1. A method for repetitively packaging a set numberof articles within a predetermined weight range, by using a plurality,n, of weighing machines, said method comprising the steps of:feedingeach of said n weighing machines with articles to be packaged; weighingsaid articles in each of said n weighing machines; calculating thenumber of articles in each weighing machine by dividing the weightmeasured by each weighing machine by a predetermined unit weight;calculating combinations of said number of articles in each weighingmachine to provide combination numbers; selecting a preferredcombination from said combination numbers, such that the totalcombination number of articles in said preferred combination is equal orclosest to said set number of articles; further calculating a new unitweight from the weight or weights measured by one or a plurality of saidweighing machines and from the number or numbers of articles in said oneor plurality of weighing machines, said new unit weight beingsubstituted for said predetermined unit weight in calculating the numberof articles in subsequent weighing and calculating operations; anddischarging and packaging said articles together from the weighingmachines comprising said preferred combination, and returning to saidfeeding step.
 2. The packaging method of claim 1, wherein said new unitweight calculated in said calculating step is determined by dividing thecombination weight of articles in the weighing machines of saidpreferred combination by the number of discharged articles.
 3. Thepackaging method of claim 1, wherein when a plurality of combinationshave combination numbers which are each equal to the set number, saidnew unit weight is calculated by dividing the median of the series ofcombination weights by the combination number of articles in thecorresponding combination.
 4. The packaging method of claim 1, whereinwhen a plurality of combinations have combination numbers which are eachequal to the set number, said new unit weight is calculated by dividingeach combination weight by the corresponding combination number to findthe unit weight for each combination, and further calculating theaverage of these unit weights to find said new unit weight.
 5. Thepackaging method of claim 1, wherein said step of calculating said newunit weight includes defining an upper and lower limit for the setnumber, dividing all or any of the combination weights in thosecombinations which lie between said upper and lower limits respectivelyby the corresponding combination numbers of articles to find therespective unit weights, calculating the average of these respectiveunit weights to find said new unit weight.
 6. The packaging method ofclaim 1, wherein said step of calculating said new unit weight includesdividing the combination weights in all combinations respectively by thecorresponding combination numbers of articles to find respective unitweights, and calculating the average of these respective weights to findsaid new unit weight.
 7. The packaging method of claim 1, wherein saidstep of calculating said new unit weight includes dividing the total ofthe combination weights in all or any combinations by the total of thecombination numbers of articles in the corresponding combinations tofind said new unit weight.
 8. The packaging method of claim 1, whereinsaid step of calculating said new unit weight includes dividing theweight of articles measured by a particular one of the weighing machinestaking part in the combinatorial counting operation by the number ofarticles in said particular weighing machine to find said new unitweight.
 9. The packaging method of claim 1, wherein said step ofcalculating said new unit weight includes calculating said new unitweight by selecting in sequence one of the weighing machines taking partfor each combinatorial counting operation, said sequence having apredetermined order, and dividing the weight of the articles measured bysaid selected weighing machine by the number of articles in saidselected weighing machine.
 10. The packaging method of claim 1, whereinsaid step of calculating said new unit weight includes dividing theweights of articles weighed by all or any of the weighing machinestaking part in the combinatorial counting operation respectively by thenumbers of articles in the corresponding weighing machines to findrespective unit weights, and calculating the average of these respectiveunit weights, to find said new unit weight.
 11. The packaging method ofclaim 1, wherein said step of calculating said new unit weight includesadding up the weights of articles weighed by all or any of the weighingmachines taking part in combinatorial counting operation to find a totalweight, adding up the numbers of articles in the corresponding weighingmachines to find a total number, and dividing the calculated totalweight by the calculated total number to provide said new unit weight.12. The packaging method of any one of claims 1 through 11, whereinafter said discharge and packaging step, the numbers of articles inthose weighing machines which were not in said preferred combination andthus have not discharged articles are stored, and the recalculation ofthe numbers of articles by dividing the weights of articles by said newunit weight is performed only for the weighing machines which dischargedarticles in the previous combinatorial operation.
 13. the packagingmethod of any one of claims 1 through 11, wherein said new unit weightto be used for combinatorial counting is renewed every nth combinatorialcounting operation, such that new unit weights to be obtained each timea combinatorial counting operation is performed are stored each timethroughout n such operations, and each time unit weights correspondingto n operations are obtained, an average value thereof is calculated foruse as said new unit weight for the following n combinatorial countingoperations.
 14. The packaging method of any one of claims 1 through 11,wherein during combinatorial counting, weights, combination weights andunit weights are processed in analog quantities.